Consumer grade ballistic concrete testing

Discussion in 'Firearms' started by oil pan 4, Apr 6, 2017.


  1. oil pan 4

    oil pan 4 Monkey+++

    I have some left over concrete I figure making concrete blocks and shooting them might be fun.
    The difference between screwing off and science is taking notes.
    So I need to select a testing size and concrete to water ratio and cure time to be consistent. The cure time needs to be the same on all samples and at least a month long.
    Do basic tests to figure out which type of admixes with cheap consumer concrete resists the negative effects bullets tend to have on concrete. Compare the the different admixes to the more expensive ones, using the same cheap concrete prepared appropriately for the application.
    Figure out which one does the best over all, and best overall cost wise if there is much difference. Then try to make it better I'm looking for affordable, off the shelf addtives or reinforcement that make concrete stronger. Searching around most interest is in making concrete more wear resistant not more penetration resistant so no easy internet answers.
    The thing that makes the concrete stronger has to be economical. Making this strength needs to be cheap.

    Eventually use higher grade concrete with 2 or 3 modifications. Then make larger heavier samples and hit them with bigger rounds to reflect real world events, aka going full scale.
    The things that I would like to test to make the concrete stronger are mixing steel with the concrete like including layers of chicken wire, stucco mesh, increasing density with vibration, vacuum to reduce air entrapment, mixing water soluble polymer hardener commonly used in tile mortar, surface treatment like epoxy, aggregate modification such as mixing broken ceramic tile, glass, volcanic material, engineered synthetic fibers, water reducers, fumed silica, plasticizer or just adding more Portland cement to make it stronger like they did in the old days.
    Then test combinations of the above if they show a positive result and see if individual improvements have increasing or diminishing returns when used together with the cheap concrete.
    Again the thing that gets mixed with concrete needs to be cheap and the method needs to scale up, for example removing the air from a yard of concrete via vacuum, I don't know how I would scale that up at the moment but I think it could be done. Or I might not be able to find enough broken tile to make a difference in an actual build. Poly hardener may be just too expensive to use to mix up in say 5 to 8 yards of concrete.
    This isn't a post about " build a wall this thick to stop this kind of round" to me a test like that is utterly useless. I don't know what you local building codes are like, I don't know what the design your PE signed off on looks like I don't know you're trying to build. So I can't say "build a wall like this".
    Due to the unlimited number of combinations of form types, thicknesses, construction methods out there I think this is as close to one size fits all as I can get.
    What say you?

    The beauty of my testing concrete sample testing is it could be used for anything.
    You can see what standard concrete will do compared to standard concrete plus something that can be affordability added to a larger scale concrete job.
    Want to build a survival dome, or some kind of small above ground shelter yep.
    Want to build a standard building with 4 inch walls and want to add something in the forms in addition to rebar to make it stronger, this applies to that.
    Making something out of concrete blocks and want to fill in the blocks with something better than standard concrete, yeah I'm testing medium workability small aggregate mixs that could flow into the block voids.
    Using ICFs and can only use 4 to 6 inches of thickness so it obviously doesn't look like a fortress and want stronger than standard concrete, that's in here.
    Build something out of concrete using standard forms that's really strong that doesn't look like a fortress, yeah.
    Calling a concrete truck and want to add something to the mix before they pour, yeah I'm testing several things like that.
    Live off grid and can only work with what you can carry in on the back of your 4x4 pickup and calling in a concrete truck is out of the question, yeah this might give you a few ideas.
    Want to make pre-cast panels you can build something out of or fortify an existing structure, well yeah.

    Update edit.
    Poly hardener test, even as little as 25% will make your concrete a little stronger.
    Additional cost: $75 per yard.
    50% poly booster helped even more for double the price.
    Is it worth it? I don't really think so.

    Stucco mesh 1 and 2 layer tests.
    Putting 1 layer of stucco mesh in the middle of the form works pretty well, but does not appear to be the best use of the mesh.
    Putting layers just below the inner and outer surfaces worked best. The stucco mesh held on to loose aggregate that normally would have been blasted away, the mesh retained most of the loose aggregate and disrupted the bullet before it hit solid concrete. A very cool result.
    I believe the additional cost was around $30 per layer per yard for a 4 inch wall.
    Is it worth it? It would appear so.
    Recommended use is at least 1 layer of stucco mesh on the outer surface and use larger aggregate. Definitely going to test this full scale.
    Also much cheaper plastic mesh preformed almost well, which cost $7 per yard, per layer in a 4 inch wall. The high velocity ejected material damaged the plastic mesh on the strike face side much worse than the steel mesh.
    The plastic mesh cast inside and on the back side the form seemed to do about as well as the more expensive stucco mesh.
    Need to test these both full scale.

    Vacuum concrete sucked. It did far worse than the control. Don't use vacuum concrete.
    Vibrated concrete did the same or worse than control samples. Don't vibrate concrete to make stronger, only do long enough to fill voids.
    Looks like air entrapment is pretty important.

    Polymer strength booster at 50% mix had some effect. The cost of wetting concrete with 50% poly booster is around $150 per yard. 25% poly booster was almost no different than the control.
    Spend your budget on something else.
    If you are trying to make the ultimate concrete and money is no object and you cant put any more steel in your forms and have a bunch of fiber in there, mesh too, sure use it in at least 50% concentration.
    Its just a lot of money for such a small improvement.

    Initial results look like adding something to the concrete that isn't a concrete ingredient such as steel mesh is the most effective use of funds.

    According to quikcrete they are saying their concrete weighs 4,500lb per yard, before you add water. Then to make it wet 1 yard needs up to 200lb of water.

    Here is a mix ratio quick reference.
    M is the number of mega pascals. Then cement : sand : gravel (by volume)
    M10- 1:3:6
    M15- 1:2:4
    M20- 1:1.5:3
    M25- 1:1:2
    M30- 1:1.5:1.1 Large agg needs to be angular and 10mm, 0.3:1 water to cement ratio by volume.
    1 Mpa is equal to about 145psi.
    When I go full scale I think I will use ammo cans as giant measuring cups.
     
    Last edited: Sep 14, 2017
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  2. ghrit

    ghrit Bad company Administrator Founding Member

    Consider whether or not you want to add stone and if so size and hardness matters.
     
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  3. Tully Mars

    Tully Mars Metal weldin' monkey

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  4. Ganado

    Ganado Monkey+++

    @Tully Mars How much do you think it added to the cost per cubic yard? just ball park figures

    ps love the gray pride you evil welding monkey! lol
     
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  5. Motomom34

    Motomom34 Monkey+++

    How much left over concrete do you have @oil pan 4? And how many things are you planning on building? You said 8 yards extra? Are you planning on selling these?

    @Ganado Fiber runs around $7 per cubic yard.
     
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  6. sec_monkey

    sec_monkey SM Security Administrator

    what are ya tryin to stop? wipe ;)
     
    Last edited: Apr 7, 2017
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  7. Tully Mars

    Tully Mars Metal weldin' monkey

    Not really sure as I knew what I wanted and just ordered it, but @Motomom34's price above sounds in the ballpark, so that would put it at just over 100 bux per yard. I also used close to two 40' flatbed trailers of rebar in that project.

    Thanks, yeah I'm getting cranky in my old age;)
     
    Last edited: Apr 6, 2017
  8. ghrit

    ghrit Bad company Administrator Founding Member

    Waugh!! Was thinking to put up a link or so to ballistic concrete, BUT. Google has so many responses to the search term "ballistic concrete" that I'd still be making links in this post until late tonight.
     
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  9. sec_monkey

    sec_monkey SM Security Administrator

    google Micro-reinforced ultra-high-performance concrete ;)
     
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  10. Tempstar

    Tempstar Praeclarum Site Supporter+

    We had 8000# concrete in the floors of the TV Station (used to be a bank) and I learned a bit about that stuff. Ramset would just bend the nails and it would take several bits per hole to drill anchors. The core driller guy said forget it. I always wondered how it would stand up to a Mosin-Nagant but felt upper management would frown on me testing it in the building.
     
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  11. Homer Simpson

    Homer Simpson Monkey+

    I know in my AO, 5 years ago 3000 psi fiber reinforced concrete was $97 a yard. A few weeks ago 3000 psi non fiber was $147 :eek: a yard, needless to say I'm still shopping that.
     
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  12. duane

    duane Monkey+++

    British during WW II used Plastic Protective Plating on some of their ships as poor mans armor against machine gun projectiles with good results. Was stone and tar on plywood sheets. The big shots wouldn't let them call it armor as that was "their" field. The concept that I like goes back to the middle ages and the first defense against cannons. An outer wall, loose sand, an inner wall, and put your emphasis on limiting the size of the hole in the outer wall. We used to put ammo boxes full of sand out a few feet from our tents with the aim of setting off the rpg or rocket far enough out that the sandbags would be stopping fragments and not the main explosion. Thank the Lord that I personally don't know if that works. Still there must have been a reason that a lot of the WW II Sherman pictures show a lot of sand bags on them. Haven't read up on it, but in tanks, there are several different "kill" approaches. You can use a solid shot that will either penetrate or cause fragments to spall off the inside of the armor and kill the crew, use a shaped charge explosive that will melt a hole through the armor and have a jet of hot gas and molten steel burn the crew and set off the ammo, or an explosive that just tears a hole in the armor. My thought is that concrete would be a lot like steel and the best defense would be a 3 layer defense using cheap sand or dirt in the middle as a defense in depth. Lots of information on that in building house walls out of plywood and stone. Look forward to your results and am really interested in the spalling effect even with a small round.
     
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  13. oil pan 4

    oil pan 4 Monkey+++

    Since I am not getting an RPG7 this year or next probably not going to be able to try that.
    I am looking forward to testing the fiber glass reinforced stuff.
     
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  14. Brokor

    Brokor Live Free or Cry Moderator Site Supporter+++ Founding Member

    If making it myself, I would hit up Alibaba, spend about $20 for 9 kg (20 lbs.) on alkali resistant (AR) chopped glass fiber and that will adequately reinforce 1 cubic yd, or 4000lbs of concrete.

    But that's just how I would do it. If I were feeling fancy, I would also get some mesh in either AR glass or carbon fiber, or add some carbon fiber strand to the mix in a 1 carbon ratio to 4 parts AR glass. Again, that's just me.
     
  15. ghrit

    ghrit Bad company Administrator Founding Member

    I think you mean 4Kpsi concrete. One yard weighs a bit under 3000 lbs ---
     
  16. Brokor

    Brokor Live Free or Cry Moderator Site Supporter+++ Founding Member

    That's light weight. Given he's using it for ballistic testing, I went with normal weight concrete, which is around 4,000 lbs.
     
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  17. oil pan 4

    oil pan 4 Monkey+++

    After much consideration I have settled on a set of test standards.
    All the small scale is going to be based around hardware store "concrete" pavers.
    That way anyone can test it.
    The control? Yes it's the hardware store concrete pavers.
    I figure if I can't improve upon the lowly $1.93 store bought concrete paver then why bother.
    The small scale samples, exactly the same size as pavers.

    I have been reading what I can find on concrete. What seems to make it stronger and what seems to make it weaker. Not enough aggregate, too much aggregate will make it weak. Air bubbles seem to be what allows the cracks to spread.
    Fibers such as fiber glass will stop or prevent cracks, polymer additives will also increase cracking resistance.
    Typically denser concrete is stronger.

    I found a pressure cooker with gasket at the scrap yard, since I'm not even going to try to ask my wife if I can use her pressure cooker. I'm thinking that could be my small scale 1 gallon concrete air removal chamber, since I already have a vacuum pump.
    Typically concrete is made up of 9% to 20% air by volume. So I think removing most of the air might be interesting. There is just not a practical way to do it large scale. Since removing the air will make it up to 20% more dense and remove those crack propagating air bubbles.

    Another test that might be kind of fun, see how long it takes to grind or drill through a sample.

    Other applications you could use this on:
    Stucco, concrete table tops and counter tops, concrete block filling.
     
    Last edited: Jun 7, 2017
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  18. ghrit

    ghrit Bad company Administrator Founding Member

    Alas, poor @Brokor. He knows a lot, but about concrete, he has an MT spot between his ears. Concrete is in my wheelhouse after a few 100K yards placed. "Normal" concrete weighs a bit under a ton and a half, regardless of mix strength. The weight is, in general NOT related to strength.
     
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  19. oil pan 4

    oil pan 4 Monkey+++

    I'm open to any suggestions.
     
  20. Brokor

    Brokor Live Free or Cry Moderator Site Supporter+++ Founding Member

    I don't care how much concrete you've placed. Arguing how much it weighs is ridiculous when all I did was reference the internet for my calculation, and I can't find a single source which says it weighs 3000 lbs per yard, but I will take your word for it because it doesn't matter. Sand? Rock? I never sat around with a scale, never poured concrete for a living in mass quantities, never claimed to be the greatest expert ever who has poured thousands of yards and swing my block around like I am the toughest guy in the room. I may have poured lots of concrete by hand before, may have done it since I was a kid. I may have mixed aggregate and tamped the forms to work out air bubbles and smoothed it out, may have worked the concrete a bit, and never once did I try to weigh it. The contractor charged per yard, and some other guy who knew more than me worried about the math because at the end of the day...it didn't matter. I hope that's the end of it. [winkthumb]

    Put it in a form, tamp it, let it dry and smack it with some lead. I would use chopped glass fiber, it's cheap and available in the link I provided. Of course, you may wish to see if Ghrit could weigh the glass for you just for the kicks.

    [LMAO] allconcreteweighs3000lbs | Survival Monkey Forums
     
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